Incidence of the winemaking technique on metal content and phenolic composition of red wines

The influence of different winemaking techniques usually used to elaborate red wines (Ganimede, prefermentative maceration, pectolytic enzymes and tannins addition, oak chips addition, delestage and conventional procedure) on the metal content was evaluated. Linear discriminant analysis was also used to characterize the respective wines in base on the metal content. By using iron, manganese and calcium as chemical descriptors, the six winemaking techniques were perfectly discriminated. As the phenolic composition is an important quality factor in red wines, a correlation study between phenolic compounds and metals was also performed. A good correlation has been found for iron, calcium and potassium with total polyphenols, tannins and flavanols reactive. Iron, zinc, calcium and potassium showed a significant correlation with anthocyanin compounds. Furthermore, higher concentrations of iron and calcium, but lesser ones of potassium, permitted to obtain red wines with a greater chromatic intensity.